is31fl3236是一款很牛逼的led控制芯片，最多可以控制36通路的led灯，配合智能音箱的麦克风阵列使用，效果非常酷炫，目前市面上很多主流的智能音箱都有用它，比如：天猫精灵、腾讯听听等。
is31fl3236是通过i2c控制的，R18上的i2c驱动是调好的。
github上可以找到is31fl3236这一类led控制芯片的通用驱动，但是这里我们可以用内核提供的i2c-dev.c来构建，用系统给我们提供的i2c-dev.c来实现一个i2c适配器的设备文件，然后通过在应用层操作i2c适配器来控制i2c设备。
（https://www.cnblogs.com/liugf05/archive/2012/12/04/2801951.html）
i2c-dev.c并没有针对特定的设备而设计，只是提供了通用的read()、write()和ioctl()等接口，应用层可以借用这些接口访问挂接在适配器上的i2c设备的存储空间或寄存器，并控制I2C设备的工作方式。但是read和write方法适用性有限。
所以用ioctl方法来操作：
一般都不会使用i2c-dev.c的read()、write()方法。最常用的是ioctl()方法。ioctl()方法可以实现上面所有的情况（两种数据格式、以及I2C算法和smbus算法）。
针对i2c的算法，需要熟悉struct i2c_rdwr_ioctl_data 、struct i2c_msg。使用的命令是I2C_RDWR。
代码语言：javascript复制 struct i2c_rdwr_ioctl_data
{
struct i2c_msg __user *msgs; /* pointers to i2c_msgs */
__u32 nmsgs; /* number of i2c_msgs */
};
struct i2c_msg {
_ _u16 addr; /* slave address */
_ _u16 flags; /* 标志（读、写） */
_ _u16 len; /* msg length */
_ _u8 *buf; /* pointer to msg data */
};针对smbus算法，需要熟悉struct i2c_smbus_ioctl_data。使用的命令是I2C_SMBUS。对于smbus算法，不需要考虑“多开始信号时序”问题。
代码语言：javascript复制 struct i2c_smbus_ioctl_data {
__u8 read_write; //读、写
__u8 command; //命令
__u32 size; //数据长度标识
union i2c_smbus_data __user *data; //数据
}首先在内核中已经包含了对s3c2410 中的i2c控制器（总线驱动）驱动的支持。提供了i2c算法（非smbus类型的，所以后面的ioctl的命令是I2C_RDWR）
代码语言：javascript复制 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
.master_xfer = s3c24xx_i2c_xfer,
.functionality = s3c24xx_i2c_func,
};另外一方面需要确定为了实现对AT24C02 e2prom的操作，需要确定从机芯片的地址及读写访问时序。
调试时可以选择make menuconfig下的i2c调试工具，如i2cget, i2cset, i2cdetect等，在
Base system -> busybox -> Miscellaneous -> ...下
led demo源码：
代码语言：javascript复制// #include <stdarg.h>
#include <iostream>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
// #include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <linux/i2c-dev.h>
#include <linux/i2c.h>
#include <sys/ioctl.h>
#include <endian.h>
#include <iostream>
#include <unistd.h>
#include <sys/syscall.h> /* For SYS_xxx definitions */
#define SLAVE_ADDRESS 0x3F
#define ADDRESS_LENGTH 2
#define DATA_LENGTH 2
#define I2C_DUMP
static int led_hI2cDevice;
static char led_devname[20]="/dev/i2c-1";
static unsigned char led_bChipAddress; /*Specify the i2c chip address*/
static unsigned char led_bAddressOffset;
#ifdef I2C_DUMP
static int debugflag = 1;
#else
static int debugflag = 0;
#endif
void sys_mdelay(unsigned int ms_delay)
{
usleep(ms_delay*1000);
}
int i2c_write(unsigned char reg_address, unsigned char val)
{
struct i2c_rdwr_ioctl_data packets;
struct i2c_msg msg[1];
unsigned char led_i2c_buf[2];
unsigned int write_len = 2; //Addr Data 2 bytes
int fd = led_hI2cDevice;
int ret = 0;
int i;
// led_i2c_buf[0] = SLAVE_ADDRESS;
led_i2c_buf[0] = reg_address;
led_i2c_buf[1] = val;
msg[0].addr = led_bChipAddress;
msg[0].flags = 0; //7 bits
msg[0].len = write_len;
msg[0].buf = led_i2c_buf;
packets.msgs = msg;
packets.nmsgs = 1;
if (debugflag)
{
printf("I2C: <START> X", led_bChipAddress<<1);
for(i=0;i<msg[0].len ;i )
{
printf(" X",(0xff& led_i2c_buf[i]) );
}
printf(" <STOP>n");
}
ret = ioctl(fd,I2C_RDWR, (unsigned long)&packets);
if (ret < 0) {
printf(" Failed: i2c_write error = %d (%s)n", ret, strerror(errno));
return -1;
}
return 0;
}
int i2c_init (unsigned char slave_address, int address_offset)
{
int i2cdev = 0;
char *devname = NULL;
led_bChipAddress = slave_address;
led_bAddressOffset = address_offset;
/* g_cbMaxI2cWrite = DEF_MAX_I2C_WRITE_LEN;
g_cbMaxI2cRead = DEF_MAX_I2C_READ_LEN;*/
devname = led_devname;
i2cdev = open(devname, O_RDWR);
printf("DEV I2C: open i2c device from %sn",devname);
if( i2cdev < 0 )
{
fprintf(stderr, "I2c device [%s] is not present.n",devname);
return -ENODEV;
}
led_hI2cDevice = i2cdev;
return i2cdev;
}
int i2c_close (void)
{
close(led_hI2cDevice);
return 0;
}
unsigned char pwm_value = 0xFF;
unsigned char pwm_half_value = 0x66;
unsigned char config_value = 0x01;
unsigned char reset_value = 0x00;
int global_en() {
i2c_write(0x4A, 0);
}
int global_disable() {
i2c_write(0x4A, 1);
}
int boot_stage_one() {
int i = 0;
int blue_start = 0x24;
while(1) {
i2c_write(blue_start, pwm_half_value);
i2c_write(blue_start - 3, pwm_half_value);
i2c_write(0x25, reset_value);
i2c_write(blue_start - 1, pwm_half_value);
i2c_write(blue_start - 4, pwm_half_value);
i2c_write(0x25, reset_value);
sys_mdelay(100);
i2c_write(blue_start - 1, reset_value);
if (blue_start - 4 <= 0) {
blue_start = 0x24;
} else {
blue_start -= 3;
}
}
}
int boot_stage_two() {
int i = 0;
int blue_start = 0x24;
while(1) {
i2c_write(blue_start, pwm_half_value);
i2c_write(0x25, reset_value);
i2c_write(blue_start - 1, pwm_half_value);
i2c_write(blue_start - 4, pwm_half_value);
i2c_write(0x25, reset_value);
sys_mdelay(100);
i2c_write(blue_start - 1, reset_value);
if (blue_start - 3 <= 0) {
blue_start = 0x24;
} else {
blue_start -= 3;
}
}
}
int blue_single_loop(unsigned int msec) {
int i = 0;
for (i = 0x24; i > 0; i -= 3) {
i2c_write(i, pwm_half_value);
i2c_write(0x25, reset_value);
sys_mdelay(msec); /*change this value to set different patterns*/
i2c_write(i, reset_value);
} //blue
}
int blue_backgroud(unsigned int msec) {
int i = 0;
for (i = 0x24; i > 0; i -= 3) {
i2c_write(i, 96);
i2c_write(0x25, reset_value);
sys_mdelay(msec); /*change this value to set different patterns*/
} //blue
}
int dirction_arrival(unsigned int sector) {
// sector has 10 available values , to simplify, just set 1 to 10
if (sector < 0 || sector > 11) {
printf("sector is only valid from 0 to 11");
return -1;
}
blue_backgroud(0); //blue_backgroud
unsigned int sector_start = (sector 6) % 12;
/* it can be reuse*/
printf("sector_start = %dn", (int)sector_start);
int left_start, right_start;
if (0 == sector_start) {
left_start = 0x23;
right_start = 0x02;
} else if(11 == sector_start) {
left_start = 0x02;
right_start = 0x05;
} else {
left_start = (12 - sector_start) * 3 - 1;
right_start = (12 - sector_start 1) * 3 - 1;
}
printf("left_start = %d, right_start = %dn", left_start, right_start);
/*fix me*/
for (int i = 0; i < 5; i) {
i2c_write(left_start, pwm_half_value);
i2c_write(right_start, pwm_half_value);
i2c_write(0x25, reset_value);
sys_mdelay(100);
i2c_write(left_start, reset_value);
i2c_write(right_start, reset_value);
if (left_start - 3 <= 0) {
left_start = 35;
} else
left_start = left_start - 3;
if (right_start 3 >= 36) {
right_start = 2;
} else
right_start = right_start 3;
}
i2c_write(left_start, pwm_half_value);
i2c_write(right_start, pwm_half_value);
i2c_write(0x25, reset_value);
return 0;
}
int dynamic_doa(unsigned int updated_sector) {
blue_backgroud(0);
int left_start, right_start;
if (0 == updated_sector) {
left_start = 0x23;
right_start = 0x02;
} else if(11 == updated_sector) {
left_start = 0x05;
right_start = 0x02;
} else {
left_start = (12 - updated_sector) * 3 - 1;
right_start = (12 - updated_sector 1) * 3 - 1;
}
i2c_write(left_start, pwm_half_value);
i2c_write(right_start,pwm_half_value);
i2c_write(0x25, reset_value);
sys_mdelay(1000);
printf("left_start = %d, right_start = %dn", left_start, right_start);
//for debug
i2c_write(left_start, reset_value);
i2c_write(right_start, reset_value);
return 0;
}
int thinking(int sec) {
blue_backgroud(0);
while (sec > 0) {
/*stage 1*/
for (int i = 0x23; i > 0; i -= 6) {
i2c_write(i, pwm_half_value);
i2c_write(0x25, reset_value);
}
sys_mdelay(100);
for (int i = 0x23; i > 0; i -= 6) {
i2c_write(i, reset_value);
}
/*stage 2*/
for (int i = 0x20; i > 0; i -= 6) {
i2c_write(i, pwm_half_value);
i2c_write(0x25, reset_value);
}
sys_mdelay(100);
for (int i = 0x20; i > 0; i -= 6) {
i2c_write(i, reset_value);
}
sec -= 1;
}
return 0;
}
int controller_init() {
//SDB low
int i;
//SDB high
i2c_write(0x4B, config_value);
for (i = 0x01; i <= 0x24; i ) {
i2c_write(i, reset_value);
}
for (i = 0x26; i < 0x4A; i ) {
i2c_write(i, config_value);
}
i2c_write(0x25, reset_value);
i2c_write(0x00, config_value);
i2c_write(0x4A, reset_value);
}
int responding() {
blue_backgroud(0);
int received = 0;
int breath_value[22] = {126, 116, 106, 96, 86, 78, 69, 61, 53, 46, 39, 33, 28, 22, 18, 13, 10, 6, 4, 2, 1, 0};
int step = 15;
int start = 21;
while(!received) {
for (int i = 0x023; i > 0; i -= 3) {
i2c_write(i, breath_value[start]);
i2c_write(0x25, reset_value);
}
if (start - 1 < 0)
start = 21;
else
start -= 1;
sys_mdelay(100);
}
}
int main(int argc, char *argv[]) {
system("echo 235 > /sys/class/gpio/export");
system("echo out > /sys/class/gpio/gpio235/direction");
system("echo 1 > /sys/class/gpio/gpio235/value");
i2c_init(SLAVE_ADDRESS, 2);
controller_init();
responding();
}
